diff --git a/data/features/dependabot-updates-composerv1-closing-down.yml b/data/features/dependabot-updates-composerv1-closing-down.yml
new file mode 100644
index 0000000000..bf8af2c8da
--- /dev/null
+++ b/data/features/dependabot-updates-composerv1-closing-down.yml
@@ -0,0 +1,5 @@
+# Reference: Issue #15951 - Deprecation notice - Dependabot updates ceases supporting Composer v1 [Deprecation]
+versions:
+  fpt: '*'
+  ghec: '*'
+  ghes: '>= 3.15'
diff --git a/data/reusables/dependabot/supported-package-managers.md b/data/reusables/dependabot/supported-package-managers.md
index 02ee125ad5..65d8752eac 100644
--- a/data/reusables/dependabot/supported-package-managers.md
+++ b/data/reusables/dependabot/supported-package-managers.md
@@ -2,7 +2,7 @@ Package manager | YAML value      | Supported versions | Version updates | Secur
 ---------------|------------------|------------------|:---:|:---:|:---:|:---:|:---:|
 Bundler | `bundler` | {% ifversion ghes < 3.15 %}v1, {% endif %}v2 | {% octicon "x" aria-label="Not supported" %}| {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} |
 [Cargo](#cargo)          | `cargo`          | v1               | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %}{% ifversion dependabot-updates-cargo-private-registry-support %}{% else %} (Git only){% endif %} | {% octicon "x" aria-label="Not supported" %} |
-Composer       | `composer`       | v1, v2           | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "x" aria-label="Not supported" %} |
+Composer       | `composer`       | {% ifversion dependabot-updates-composerv1-closing-down %}v2{% else %}v1, v2{% endif %}         | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "check" aria-label="Supported" %} | {% octicon "x" aria-label="Not supported" %} |
 | {% ifversion dependabot-version-updates-devcontainer-support %} |
 [Dev containers](#dev-containers) | `devcontainers`         | Not applicable               | {% octicon "check" aria-label="Supported" %} | {% octicon "x" aria-label="Not supported" %} | {% octicon "x" aria-label="Not supported" %} | {% octicon "x" aria-label="Not supported" %} | {% octicon "x" aria-label="Not supported" %} |
 | {% endif %} |